What are hair dyes?
- Hair dyes are used to change hair colours.
- Hair dyes may be made of natural ingredients or synthetically derived.
- The ones that we have in Malaysia are registered with the National Pharmaceutical Control Bureau bearing the general notification number of ‘NOT’ followed by 8 digits and the alphabet ‘K’; for example NOT08154562K.
How do hair dyes work?
- Synthetic hair dyes
- They are hair dyes with chemicals which open up the cuticle scales on the outside of the hair shaft.
- The cuticle scales close again after processing.
- If the hair is processed too often, the cuticle does not close as tightly, and the hair shaft becomes very fragile.
- Natural hair dyes
- The hair dyes with natural ingredients, however coat the outer scaly layer of the hair shaft instead of penetrating the hair shaft.
- The natural pigments of the hair shine through the colour layer, thus the new hair colour is the resultant of the combination of the original colour and the applied hair colour layer.
There are basically three types of hair dyes as listed below.
- Temporary hair dyes
- They are in the forms of gels, mousses, sprays and rinses
- They simply stay on the surface of the hair
- They are washed out with the next shampoo, therefore they need to be re-applied after each shampooing
- Semi-permanent dyes
- They are in the forms of liquids, gels, or aerosols
- Their molecules are smaller than those of temporary hair dyes
- They penetrate into and adhere to the hair shaft.
- They are usually applied daily until a dark enough shade is achieved, after which it may be used less often to maintain the colour.
- They do not wash off readily or run when the hair gets wet
- Permanent dyes
- They require more work to apply, but the hair colour lasts until the new hair – “roots” – grows in.
- They usually contain hydrogen peroxide; therefore they cover grey hair more effectively and can be used to lighten hair colour, unlike other dyes.
- They penetrate deeply into the hair shaft, and get locked within it due to a series of chemical reactions that occur while the dye is applied.
- They generally cannot be washed out with shampoo; however repeated shampooing may reduce the colour over time.
Ingredients in hair dyes
They are basically plant derived such as henna, or synthetically derived like coal tar or petroleum. Take extra caution when choosing hair dyes as some may contain substances harmful to users.
Do’s and Don’ts
- Ask your hair stylist which products he/she recommends
- Choose temporary hair dyes if possible, since they cause the least damage to the cuticle.
- Check out the registration number of the product, as well as the batch number, manufacturing date and expiry date.
- Check out the ingredients of the hair dyes, some ingredients may be harmful or cause allergic reactions.
- Pre-test for a possible allergic reactions.
- Adhere to the instructions of use
- Use gloves when applying hair dye.
- Ensure the hair dyes do not stain your skin
- Rinse your scalp thoroughly with water after use.
- Watch out for side effects of hair dyes such as dry scalp or hair loss or irritant skin.
- Report any incidents or adverse reactions concerning hair dyes to the authority and shows the related hair dye product.
- See your doctor if you develop significant skin reactions or adverse reaction.
- Apply hair dyes on areas other than the intended areas especially the eyebrows or eyelashes because they can cause swelling, inflammation, and susceptibility to infection.
- Leave the dye on your head any longer than necessary..
- Mix the ingredients of the hair dyes with other chemicals or natural products not intended for use in hair colouring..
- Keep or use any hair dye that has extended its expiry date..
- Use permanent hair dyes often, because they can damage the keratin protein.
- Keep hair dyes away from children to prevent ingestions and other accidents.
- Keep hair dyes in a cool, dry place.
20 March 2015
Ainul Salhani bt. Abd Rahman
Yam Chiew Fong
Jasmine Lee Yee Chen (2015)